1. Field of the Invention
The present invention relates to a power supply adapter and a power supply system for supplying power to a broadcast receiver such as a television receiver.
2. Description of the Related Art
Common broadcast receivers, such as common television receivers, especially small broadcast receivers, are driven by receiving DC power as supplied from a power supply adapter via a cable, and receive a broadcast signal as supplied from an outdoor antenna via a coaxial cable. Such common broadcast receivers have design constraints, e.g., difficulty in miniaturization, because of the need to secure space for an inlet, which is a connection section for receiving the power as supplied from the power supply adapter via the cable, and a connector, which is a connection section for receiving the broadcast signal as supplied from the outdoor antenna via the coaxial cable. In addition, it is not desirable in terms of visual appearance and for safety reasons that a plurality of cables, such as the power supply cable and the antenna coaxial cable, lie around the broadcast receiver. Moreover, that produces a constraint that limits locations where the broadcast receiver can be installed.
There have already been proposed techniques for allowing both the power supply and the transmission of the broadcast signal to be achieved with use of a single cable. According to one such technique, for example, both supply of the DC power from the broadcast receiver, such as the television receiver, to a satellite broadcast antenna, which requires the power supply, and input of the broadcast signal from the satellite broadcast antenna into the broadcast receiver are achieved with use of a single coaxial cable. That is, the broadcast receiver supplies the DC power to the satellite broadcast antenna via the transmission cable, while the satellite broadcast antenna supplies the broadcast signal to the broadcast receiver via the same transmission cable (see Japanese Patent Laid-open No. Hei 7-128426).
In the above known technique, both the supply of the DC power from the broadcast receiver to the antenna and the supply of the broadcast signal from the antenna to the broadcast receiver are achieved with the use of the single transmission cable, which connects the broadcast receiver and the antenna. This technique is applicable only when the antenna that requires the supply of the DC power from the broadcast receiver is used.